Ventilating apparatus

ABSTRACT

A ventilating apparatus for mounting in a roof and comprising a central shaft for exhausting spent air from the ventilated room, a surrounding annular duct divided in an upper and a lower section by means of a transverse partition wall secured to the periphery of an exhaust blower wheel located in the central shaft. Separate blower vanes are secured to the upper and lower face of the partition wall for delivering fresh air from the ambient and recirculated air from the room, respectively, to a mixing chamber surrounding the annular duct and opening into the room. Individually adjustable valve means are provided in the inlet openings from the upper and lower duct sections to the mixing chamber.

United States Patent Iversen [54] VENTILATING APPARATUS [72] Inventor: Christian Eduard Iver-sen, Odense,

Denmark Primary Examiner-Edwardj. Michael Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [73] Assignee: Nordisk Ventilator Co., Aktieselskab, Naestved, Denmark [57] ABSTRACT [22] Filed; April 13, 1971 A ventilating apparatus for mounting in a roof and comprising a central shaft for exhausting spent air PP N05 133,570 from the ventilated room, a surrounding annular duct divided in an upper and a lower section by means of a transverse partition wall secured to the periphery of 9 Foreign Apphcatwnm Data I an exhaust blower wheel located in the central shaft. April 13, 1970 Denmark ..l843/70 Separate blower vanes are secured to the upper and lower face of the partition wall for delivering fresh air [52] US. Cl ..98/62, 98/116 from the ambient and recirculated air from the room, [51] Int. Cl ..F23l 17/04 r sp c y, t a i g am rr ng t n- [58] Field of Search ..98/66, 116, 8-10 nular ductand opening into the room. Individually adjustable valve means are provided in the inlet openings [56] R f n Cited from the upper and lower duct sections to the mixing chamber. UNITED STATES PATENTS I 6 Claims, 2 Drawing Figures 3,263,906 8/ 1966 Ward ..98/l l6 X 3,430,549 3/1969 Hershey ..98/62 5 l 2, 2 I g a, -2

' I T 2a. 271 3 82 M 4 2, 32 I2 2 I I l A l 30 l8 I7 37 x l 16 Z any 29 9 14 a7 I I4 l PHENTEDSEWWTZ 3.888.681 SHEET 1 [IF 2 VENTILATING APPARATUS BACKGROUND OF THE INVENTION This invention relates to a roof mounted ventilating apparatus, particularly but not exclusively for use in stables, of the kind comprising a central exhaust shaft and an annular duct, coaxial therewith, for the intake of fresh air, and wherein fan impellers, which are separate, but mechanically interconnected and driven by the same motor, are mounted in the shaft and the duct, respectively.

Ventilation plants including such apparatus have certain advantages in comparison with plants in which the spent air is exhausted by means of fans mounted in the roof, while fresh air is taken in through valves in the outer walls of the room. The risk of harmful draughts in the room to be ventilated due to wind effects upon the valves in the walls is avoided and, moreover, it is possible to create a controlled recirculation of the air in the room in a comparatively simple way. A known ventilating apparatus of the kind referred to comprises two axial fan impellers which are mechanically coupled together and located in the central shaft and the surrounding annular duct, respectively, while an adjustable double valve or damper is mounted above the impellers and adapted to open a by-pass between the exhaust shaft and the surrounding intake duct and at the same time to throttle the upper part of the flowpassages opening into the surroundings. With such apparatus, the possibilities of control are limited to a variation of the ratio of mixture between fresh air and recirculated air, while the quantities of air sucked from the room and blown into the room per unit of time are constant.

SUMMARY OF THE INVENTION According to the present invention there is provided a ventilating apparatus for mounting in a roof, comprising means defining a central exhaust shaft, first blower means mounted in said shaft for exhausting air from a room below the roof to the surroundings, means defining an annular duct coaxially surrounding said central shaft and open at both ends, a partition wall located intermediate said duct ends and shaped so as to substantially obturate said duct, second blower means located in said duct at one side of said partition wall and third blower means located in said duct at the opposite side of said partition wall, means defining an annular mixing chamber coaxially surrounding said duct at the level of said partition wall and having an air outlet, openings in said duct defining means for providing communication between said mixing chamber and said duct on both sides of said partition wall, valve means in said openings, individually operable means for adjusting said valve means to vary the areas of said openings, and a motor drivingly connected to said first, second and third blower means.

With an apparatus according to the invention it is possible, not only to change the mixing ratio between fresh air and recirculated air but also to vary separately the absolute rates, at which each of these two fractions are blown into the room ventilated by means of the apparatus, and hence the total delivery rate of the apparatus. Consequently, a major advantage of the invention is that it increases the possibilities of controlling the ventilation in accordance with a plurality of varying, pertinent factors such as the number and kind of animals present in the room to be ventilated and the outdoor climate, so that the apparatus can be better adjusted to comply with the varying requirements for replacement of spent air and circulating air velocities in the ventilated room.

The partition wall in the annular duct may be' recirculating air take place in the radial impellers,

which reduce the losses in power.

The separately adjustable valve means may comprise two cylindrical shells which are axially displaceable along associated parts of the outside of the annular duct. With valve means of this simple shape the manufacture is less expensive and the risk of dust and condensate being deposited on the valves is reduced.

Furthermore the valve means are easily accessible for inspection and repair, if necessary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 Shows a vertical elevantion, partly in section, of a ventilating apparatus embodying the invention and mounted in the roof of a stable, and

FIG. 2 shows half a plan view on line 11-11 in FIG. 1.

DETAILED DESCRIPTION The ventilating apparatus illustrated in the drawings is mounted in the ridge of a roof 1 and comprises an outer cylinder 2 of sheet metal and an inner sheet metal cylinder 3, which is coaxial with the cylinder 2, the cylinders being interconnected by means of a plurality of stay bolts 4, one of which is shown in FIG. 1. A conical hood 5 is secured at a distance above the upper end of the cylinder 3 by means of braces 6, and a further hood 7 shaped as a truncated cone is secured to the cylinder 3 at a distance above the upper mouth of the cylinder 2, with which it isconnected by means of braces 8.

At their lower ends, the two cylinders 2 and 3 ter-' each other by means of vertical stay bolts 14 which I consequently carry and center or align the lower cylinders 10 and 11. To the bolts 14 there are furthermore secured two dished plates 15 and 16 located at the level of the lower edges of the upper cylinders 2 and 3 and the upper edges of the lower cylinders 10 and 11 respectively. The plates 15 and 16 are fixed axially by 'means of spacing bushes or sleeves 17, which surround the bolts 14, and associated nuts.

The central apertures in the plates 15 and 16 are slightly larger than the outer diameter of the associated cylinders 2 and 10, and in the annular slots thus formed, two cylindrical valve members or dampers 18 and 19 are vertically displaceable. As shown, the dis placement of each damper along the associated cylinder can be controlled by means of oblique slots 20 and 21 provided in the dampers and engaging with guide pins 22 secured to the associated cylinder 2 and 10, respectively. To each damper there is furthermore secured an outwardly projecting actuating arm 23 carrying a radially adjustable slide block 24 which, e.g., by means of a chain or wire, can be connected to a thermostat-controlled servomotor, which may be electric, hydraulic or pneumatic. Each wire may, in a way known per se, be connected to-a return or reset spring. It will appear that the oblique course of the guide slots 20 and 21 causes an axial displacement of each damper 18 or 19in response to a turning of the damper around the axis of the cylinder by means of the associated actuating arm 23. I I

Internally of the central shaft 25, which is defined by the inner cylinder 3 and the extension thereof, an electric motor 26 is secured by means of arms 27. On the downwards-directed shaft end of the motor a fan or blower impeller having a hos 28 and a plurality of axial impeller vanes 29 is secured. At'their periphery, the vanes 29 are secured to a ring 30 which substantially occupies the axial space or clearance between the cylinders 3 and 1 1 thus forming part of the outer defining wall of the-shaft 25. To the outside of the vertical ring 30, a horizontal ring 31 is secured approximately midway between the ends of the ring. On its upper side and also on its lower side the ring 31 carries a plurality of radial vanes 32 which extend to the circumference of the outer cylinders 2 and 10, see also FIG. 2, so as to formtwo radial fans or impellers which draw air from the room 9 through the duct between the two cylinders 1 l0 and 11 and from the ambient or open air through the upper annular duct between the cylinders 2 and 3, respectively. Simultaneously, the fan formed by the axial vanes 29 produces a vertical flow of air through the inner shaft 25 from the room 9 into the open air through the apertures between the upper edge of the shaft and the hood 5. The said air flows are indicated by means of arrows in FIG. 1.

As shown in FIG. 1, an adjustable damper or louvre comprising a plurality of lamellae 33 pivotally mounted upon radial shafts may be provided at the bottom end of the shaft 25 to very the cross-section of the inflow passage to the shaft 25. The pivoting of the lamellae 33 may be controlled by means of an actuating arm 35 which is secured to the boss 34 of the louvre and carries a radially adjustable slide block 36 which, in a similar way as the blocks 24 mentioned above, can be connected to a thermostat-controlled servomotor.

At their outwards-facing edges the'two dished plates and 16 are slit radially to form a plurality of separate tongues 37, see also FIG. 2, and the comparatively elastic tongues 37 are connected in pairs by means of bolts 38 which permit an individual or local adjustment of the cross-section of the slot between the tongues of each pair through which air is blown into individual zones of the room 9. In connection with each bolt 38, a coil spring (not shown) may be provided between the two tongues 37 which are thus biased away from one another.

When the motor 26 is operative, the combined blower or fan unit, comprising the axial fan having vanes 29 and thetwo radial fans having vanes 32, causes-a flow of fresh air to be taken in through the annular duct between the cylinders 2 and 3, while a quantity of recirculation air is sucked away from the room 9 through the duct betweenthe cylinders 10 and 11, and' a further quantity of air is exhausted from the room through the central shaft 25. The two first mentioned air flows are mixed in the annular mixing chamber located between the plates 15 and 16 and are returned to the room 9 through the individually adjustable slots or nozzles between the tongues 37. It will be seen that by separately or individually controlling the opening degree of dampers 1'8 and 19, asexplained above, it is possible to vary not only the mixing ratio between fresh air and recirculated air, but also the total quantity or rate of each of the two air flows. correspondingly, it is possible by means of the damper 33, 34 at the lower end of the shaft 25 to adjust the quantity of exhausted air independently of the two other quantities of air. By suitable dimensioning of the mixing chamber it is possible toachieve a satisfactory mixture of fresh and recirculating air, and when the radial vanes 32 are shaped in such a way that the air leaves the vanes substanu'ally radially, guide or bafile vanes in the mixing chamber may be dispensed withLAs shown in FIG. 1, there may be provided conical guide walls or baflles at the transition from the annular ducts to thetwo radial fan impellers for guiding the flow of air towards the radial inflow aperture of the fan impellers.

In FIG. 1, the guide slots of the rotatable cylindrical dampers are shown as being rectilinear, but they might alternatively have a curved shape in order'to attain a desired dependency between the rotation of each damper and the corresponding axial adjustment of the damper opening. it will also be obvious that the guide slots might be provided in the stationary duct cylinders and the pins be secured to the dampers, and that it would be possible to use any other suitable mechanism than that shown for effecting the axialdisplacement of the dampers. The vanes 32 of the two radial impellers may be identical or different and may have any known and suitable shape such as double-curved. The mixing chamber may generally have a polygonal circumference, e.g., a quadrilateral circumference, or be provided with a number of separate injection nozzles to the room to be ventilated. In the latter case, guide ducts may be necessary.

It may be mentioned, as an additional advantage of the invention, that the pressure in the ventilated room may at will be adjusted to be equal to, lower than or higher than the atmospheric pressure. 1

What is claimed is:

l. A ventilating apparatus for mounting in a roof, comprising means defining a central exhaust shaft, first blower means mounted in said shaft forexhausting air from a room below the roof to the surroundings, means defining an annular duct coaxially surrounding said central shaft and open at both ends, a partition wall located intermediate said duct ends and shaped so as to substantially obturate said duct, second blower means located in said duct at one side of said partition wall and third blower means located in said duct at the opposite side of said partition wall, means defining an an-- let, openings in said duct defining means for providing communication between said mixing chamber and said duct on both sides of said partition wall, valve means in said openings, individually operable means for adjusting said valve means to vary the areas of said openings, and a motor drivingly connected to said first, second and third blower means.

2. A ventilating apparatus as claimed in claim 1, wherein said partition wall is secured to the periphery of said first blower means, and wherein said second and third blower means comprise radial blower vanes secured to the axially opposed sides of said wall.

3. A ventilating apparatus as claimed in claim 1, wherein the means defining said mixing chamber comprises axially spaced end walls extending transversely of saidouter annular duct with a radial clearance therebetween, and said valve means comprises two cylindrical shells extending into said mixing chamber through said clearance.

4. A ventilating apparatus as claimed in claim 3,

wherein said means for adjusting the valve means comprises interengaging pins and inclined slots provided in said shells and the wall of said annular duct, respectively, and means for rotating each of said shells about the axis of said annular duct.

5. A ventilating apparatus as claimed in claim 1,

wherein the means defining said mixing chamber com- 

1. A ventilating apparatus for mounting in a roof, comprising means defining a central exhaust shaft, first blower means mounted in said shaft for exhausting air from a room below the roof to the surroundings, means defining an annular duct coaxially surrounding said central shaft and open at both ends, a partition wall located intermediate said duct ends and shaped so as to substantially obturate said duct, second blower means located in said duct at one side of said partition wall and third blower means located in said duct at the opposite side of said partition wall, means defining an annular mixing chamber coaxially surrounding said duct at the level of said partition wall and having an air outlet, openings in said duct defining means for providing communication between said mixing chamber and said duct on both sides of said partition wall, valve means in said openings, individually operable means for adjusting said valve means to vary the areas of said openings, and a motor drivingly connected to said first, second and third blower means.
 2. A ventilating apparatus as claimed in claim 1, wherein said partition wall is secured to the periphery of said first blower means, and wherein said second and third blower means comprise radial blower vanes secured to the axially opposed sides of said wall.
 3. A ventilating apparatus as claimed in claim 1, wherein the means defining said mixing chamber comprises axially spaced end walls extending transversely of said outer annular duct with a radial clearance therebetween, and said valve means comprises two cylindrical shells extending into said mixing chamber through said clearance.
 4. A ventilating apparatus as claimed in claim 3, wherein said means for adjusting the valve means comprises interengaging pins and inclined slots provided in said shells and the wall of said annular duct, respectively, and means for rotating each of said shells about the axis of said annular duct.
 5. A ventilating apparatus as claimed in claim 1, wherein the means defining said mixing chamber comprises two dished plates rigidly secured to and extending radially from said annular duct, the outer edge zones of said plates being slit so as to form a plurality of axially opposed pairs of tongues, and means for individually varying the axiAl spacing between the tongues of each pair.
 6. A ventilating apparatus as claimed in claim 1, comprising further adjustable valve means mounted in the bottom end of said central exhaust shaft and means for varying the opening degree of said further valve means. 